build: Fix build and behaviour on OpenBSD.

Summary:
OpenBSD does not have strchrnul. Also, fix range
issue with window size.

The geometry is broken on OpenBSD and DragonFlyBSD.
A previous patch solved this issue. Range was
changed to <= 0, but needs to be <= 1 to  ensure
the terminal opens and displays content.

Reviewers: billiob

Reviewed By: billiob

Differential Revision: https://phab.enlightenment.org/D9157

src/bin/termio.c

@@ -3010,7 +3010,7 @@ _smart_size(Evas_Object *obj, int w, int h, Eina_Bool force)
 
    EINA_SAFETY_ON_NULL_RETURN(sd);
 
-   if ((w <= 0) || (h <= 0))
+   if ((w <= 1) || (h <= 1))
      {
         w = 80;
         h = 24;

src/bin/termptyesc.c

@@ -3409,6 +3409,23 @@ _eina_unicode_to_hex(Eina_Unicode u)
    return -1;
 }
 
+#if defined(__OpenBSD__)
+char *
+strchrnul(const char *s, int c)
+{
+   const char *p = s;
+
+   while (*p)
+     {
+        if (*p == c)
+          return (char *)p;
+
+        ++p;
+     }
+   return (char *)  (p);
+}
+#endif
+
 static int
 _xterm_parse_color(Termpty *ty, Eina_Unicode **ptr,
                    unsigned char *r, unsigned char *g, unsigned char *b,